Steerable medical devices can be used in any application when a medical device needs to be steered, or bent. For example, steerable delivery devices can be used to deliver, or guide, medical devices or instruments to a target location within a subject. The delivery devices provide access to target locations within the body where, for example, diagnostic, therapeutic, and interventional procedures are required. Access via these devices is generally minimally invasive, and can be either percutaneous, or through natural body orifices. The access can require providing a guiding path through a body lumen, such as, for example without limitation, a blood vessel, an esophagus, a trachea and adjoining bronchia, ducts, any portion of the gastro intestinal tract, and the lymphatics. Once a delivery device has provided access to the target location, the delivery device is then used to guide the medical device or instrument to perform the diagnostic, therapeutic, or interventional procedure. An example of such a delivery device is a guide catheter, which may be delivered by steering it to its required destination, tracking it along a previously delivered guide wire, or both. The list of components being delivered for use percutaneously is large and rapidly growing.
Minimal outer dimensions of delivery devices can be important for minimizing the injury associated with delivery. Minimizing the wall thickness of a delivery device provides additional space for the medical device to be guided, while minimizing the injury associated with entry into the subject and the closure needed. Flexibility of a delivery device is important in allowing the guiding device to track or be steered to its target destination along tortuous paths while minimizing injury to the intervening tissues. A delivery device may also need to have compressive and tensile properties sufficient to support its delivery to the target site. When tracking around bends in the body, any kinks created in a guiding device can create an obstruction to the delivery of the medical device. When used as a steerable device, the distal end of a delivery device is preferably deflectable over a range of bend radii and responsive to the steering controls. A delivery device may also need to support torque transmitted from the handle to the distal region.
Once a delivery device is in place the delivery device preferably also supports torque around a distal bend such that the medical device may be rotated into position while sustaining some contact loads. Additionally, once in place the guiding device preferably is sufficiently stiff to support and guide the medical device to its target destination. A guiding device may also remain stable and not shift from one state of equilibrium to another either spontaneously or under the influence of forces being imparted to it from the delivery of the medical device or its own control mechanisms. As a delivery device often travels down fluid-filled lumens such as, for example without limitation, blood vessels, it should additionally incorporate a seal against fluids impinging upon its periphery and another at its distal end which interfaces with the medical device to maintain a seal around the delivery device.
There exists a need for improved steerable medical devices, such as steerable delivery devices.